Nematodes are soil-dwelling, microscopic, un-segmented, round worms that may be parasitic or beneficial to a plant growing in the soil. Depending on the species of the nematode and their numbers in the soil, the nematode may be capable of causing a decline in grasses such as, for instance, turf grass. In established turf grass applications, contact nematicides come in granular or spray formulations and are typically watered-in after application. These nematicides are usually toxic to human and animals and have to be handled with extreme care. Sesame oil has been found as one naturally derived control for the parasitic nematodes which is safe for application. However, sesame oil is not water dispersible. Thus, there is a need for a commercially available spray sesame oil formulation.
Plant parasitic nematodes infect many major food and fiber crops, as well as turf grasses and ornamentals, and cause significant reduction in crop yield and quality. Nematodes have been estimated to cause annual crop losses of about $78 billion worldwide (from the report “Plant & Soil Nematodes: Societal Impact and Focus for the Future”, sponsored by USDA-CSRS and The Society of Nematologists). Most plant parasitic nematodes feed on the roots, but a few species attack above-ground plant parts. Damage from nematodes is primarily due to feeding and wounding, which in turn affects water and nutrient absorption, and can lead to secondary infections by bacterial and fungal pathogens. In addition, root-feeding nematodes have been implicated in the transmission of viral diseases. Plant-parasitic nematodes seldom kill plants outright. A loss of yield or quality can occur without specific above-ground symptoms. Sometimes these losses are attributed to other pests, fertility problems, or improper water management. The symptoms of nematode damage may vary among crops and are generally manifested as root galling, lesions, premature wilting, chlorosis and overall reduction in plant vigor.
The most popular means of controlling nematodes include the use of soil fumigants such as methyl bromide, or non-fumigant nematicides such as organophosphates and carbamates. These and most other conventionally used nematicides are toxic to mammals and other non-target organisms, pose a potential threat to the environment and ground water, and may leave chemical residues in food products. Resistant varieties, cultural practices such as rotation, organic amendments, and even biological control have been used with varying degrees of success to control nematodes. In the U.S., there are approximately 13,000 golf courses representing 1.2 million acres and up to 85 million households representing 17 million acres of residential turf. When recreational, commercial, and institutional areas are accounted for, total turf in urban areas is estimated at around 30 million acres. According to the 1998 and 1999 Pesticide Industry Sales and Usage Report, up to 85 million pounds of pesticide active ingredient were applied by consumers for residential pest control while close to 15 million pounds of pesticide active ingredient were professionally applied to golf courses.
Consumers apply pesticides to lawns mainly to control nuisance pests (e.g., ants, fire ants, fleas, stinging insects, and mosquitoes), while commercial lawn care companies focus on pests that damage turf (e.g., grubs, sod webworms, cinch bugs, and European crane fly). Herbicides are applied to control crabgrass and dandelions as well as a variety of other weeds. The use of pesticides on turf poses challenges to human health and the environment. A U.S. Geological Survey analysis of 20 major river basins and aquifer systems reported that insecticides used around homes, gardens, and in commercial and public areas were often found in streams at levels above water quality guidelines. The results of pesticide monitoring of residential runoff indicate that the most widely used and marketed herbicides and insecticides are routinely found in urban runoff in different regions of the country.
According to the United States Environment Protection Agency's Pesticide Incidence Data Reporting System, a total of 31,410 incidents relating to the use of pesticides on lawns were reported over the period between 1995 to 2002. The major categories of incidents were human exposures, domestic animal exposures, and damage to non-target plants. While no severe human incidents were reported for insecticides or herbicides, a large percentage of reports were on minor incidents involving humans. A smaller percentage of reports involved domestic animals or non-target plants. Significant pesticide exposure to humans and the environment can occur because of misuse. Thus, a need exists for a bio-based and bio-degradable nematological composition that is safe for application to plant material and grasses and is not toxic towards mammals.
There are many natural occurring materials which are known effective as herbicides or insecticides. There are many favorable reasons to employ a natural occurring product in the control of undesirable organisms such as soil nematodes. Natural decomposition in the soil and non-injuring to high life forms rank among the most noteworthy. Hence, the use of compositions derived from the sesame plant falls into this category of beneficial, economic and environmental considerations.
Sesame is from the generic Sesamum, a member of the Pedaliaceae family. The plant is grown primarily for its seed and oil expressed therefrom. Sesame oil is from sesame seed, of the cultivated Sesamum indicum. There are about seventeen wild species reported as occurring in Africa and two in India. Sesamum indicum L is an herbaceous plant growing several feet high with a vegetative cycle of only 3 or 4 months. Sesame is one of the highest-yielding, non-perennial oil plants.
Sesame oil is reported as a synergist with certain insecticides—U.S. Pat. No. 2,202,145 (May 28, 1940); U.S. Pat. No. 2,463,324 (Mar. 1, 1949). U.S. Pat. No. 2,463,324 discloses that sesame oil contains a material which is a synergist for certain insecticides, such as pyrethrum.
Sesame oil, meal and extracts of the sesame plant have been found to contain a mixture of unsaponifiable materials such or sesamin, sesamolin and sesamol. U.S. Pat. No. 4,442,092 describes a nematocidal composition containing as an active ingredient(s) therein sesame plant extracts including roots, seeds or stalks, oils and acids extracted therefrom, but primarily sesamin, sesamolin and sesamol. However, the compositions prepared are not stable in water and contain hazardous chemicals such as xylene (see, U.S. Pat. No. 4,442,092, Column 3 lines 55-60) to produce the emulsifiable concentration formulations. Consequently, a water dispersible nematological or herbicidal composition that is based on bio-degradable and bio-renewable ingredients and that can be sprayed on easily to the land by adding water is needed in the art.